Place noodles in large heatproof bowl, cover with boiling water; separate with fork, drain.
Heat 1 tablespoon of the oil in wok; stir-fry pork, in batches, until browned. Remove from wok.
Separate leaves and stems from gai lan. Heat remaining oil in wok; stir-fry gai lan stems until tender. Add gai lan leaves and garlic; stir-fry until gai lan wilts. Return pork to wok with noodles, sauces and sugar; stir-fry until hot.
Make a well in centre of noodles, add egg; stir-fry egg until egg and noodle mixture are combined, season to taste.
Traditionally, this recipe is known as pork pad see ew.